Mini F CLamps

[MrBowcat]

Morning all.


For some time I have been after some small friction clamps like these from ModelsRGo.





Unfortunately this company seem to have closed down some time ago and the clamps are like the proverbial hens teeth. I wanted some as they would be useful on occasion when you want to hold something together but not exert spring clamp pressure, for example when holding an aircraft fuselage together for gluing. The advantage of these clamps is that with only friction holding the jaws together they can be adjusted to just light finger pressure.


Every now and then I have a look online to see if any have become available or if anyone else has started making them, but to date no joy. So I decided to make one to see how difficult it would be. Turns out, not that difficult at all. This one is only a prototype with materials I had to hand, I will test it out and if it works OK will make some more, possible using aluminium for the jaws.








No doubt for anyone with a 3D printer this would be a simple job, it took me a couple of hours in my workshop with a pillar drill, a bandsaw and a lathe.

[Kevthemodeller]

I've got some of those. They're ok but IMHO they don't live up to their hype and aren't massively better than the all blue plastic type once you've suck some foam on the jaws.

[digger303]

I want to be the first to congratulate you on making your own. As far as I can see with the set I have the holes for the rod where they slide through.....if that makes any sense are quite loose. ROD being 5mm in diameter and the hole through which it slides being as close as I can make out 5.5mm. The rubber pad on the jaws are 5mm thick and of a very dense foam. Needs to be thick enough to mold around some parts.

When I bought my set they were so hard to find too and then they had another production run and I got lucky. I did have to order from the UK though. Maybe your work will entice them into another batch

I hope this is of some use to you.
cheers

Ps....I like mine a lot and I have a set of the plastic ones with the v cut into the jaws and I find them to be good , but finicky to use.

[MrBowcat]

Cheers Digger.

That's interesting about the hole/rod sizes, I assumed they would have to be closer to ensure they gripped well.

My holes are 6.3mm, and the rod was taken down to this size (+/- 0.01 mm) on the lathe, then polished with sandpaper until a firm sliding fit was achieved. Maybe the tolerances don't need to be as tight, although the material of the jaws may also come into play. Not sure how much "give" the plastic of the originals has, my jaws are made from Corian which has no give.

[digger303]

Cheers Digger.

That's interesting about the hole/rod sizes, I assumed they would have to be closer to ensure they gripped well.

My holes are 6.3mm, and the rod was taken down to this size (+/- 0.01 mm) on the lathe, then polished with sandpaper until a firm sliding fit was achieved. Maybe the tolerances don't need to be as tight, although the material of the jaws may also come into play. Not sure how much "give" the plastic of the originals has, my jaws are made from Corian which has no give.

No idea what Corian is, but assume it is some type of resin.
The jaws do flex a little towards the tip as they narrow in. I assume the jaws grip and lock into place because they are allowed to jam and if the holes are too tight this doesn't happen. Perhaps as you say the type of material may have a sticky ness factor. They do seem to be a hard plastic material.

[Twokidsnosleep]

Sweet work, I love homemade stuff. 99 times out of 100 they are better than the originals
I have a few plans for similar clamps made of wood<for woodwork, just haven’t made them yet

[MrBowcat]

Cheers Scott.

Digger, Corian is a worktop material, according to the blurb "Corian® Solid Surface is a solid, nonporous, homogeneous surfacing material, composed of ~1/3 acrylic resin (also known as polymethyl methacrylate or PMMA), and ~2/3 natural minerals."

I have a load of off cuts as I primarily use it in knife making, it's good for handles, spacers, etc and comes in loads of colours. It works very much like wood and can be drilled and sawn without breakout, but has zero give. It can get brittle if too thin though. It also sands and polishes up to a beautiful finish so I have also used it to make coasters, pens, etc.

[RangerNeil]

They look like Toolmakers clamps but without the threading on the rods.
Have you considered threading them rather than relying on friction?
I use my old Toolmakers clamps for similar functions and the only draw back is the weight of them being solid steel.

[MrBowcat]

I have thought about it Neil as with a fine enough thread very fine adjustment could be achieved. Only issue is making tool makers clamps is a hell of a lot more complicated, and I would definitely need to make them from metal for the threads. Not sure if they would then be too heavy for modelling??

[RangerNeil]

I have thought about it Neil as with a fine enough thread very fine adjustment could be achieved. Only issue is making tool makers clamps is a hell of a lot more complicated, and I would definitely need to make them from metal for the threads. Not sure if they would then be too heavy for modelling??

I find that whatever I clamp has to be supported else the weight of the metal clamp can distort things else where. That said for clamping slightly angled surfaces they are excellent.

For the ones you are working on - have you tried a hard nylon for the shafts? That can be threaded nicely. Not sure about the material for the blocks as I've never worked with that. Actual threading doesn't need to be as strong as steel because its not going to take anything like the stress that metal ones are designed for.

[MrBowcat]

So far I've just prototyped with the materials to hand. I might get some ali for the jaws, the thread would probably need to be steel.

[dogsbody]

I bought this set of small " C " clamps at a craft store a few years ago:





I have added some small clear pads/cork pads and stuck them onto the clamp surfaces. They work quite well and the pads stop any slippage and/or scratching of a model's surfaces. They can be mounted vertically in the round, black plastic base.

The other all-black clamp is one I found on the floor of the extraction plant I worked in. It was just laying there, so I picked it up and brought it home.






Chris

[RangerNeil]

So far I've just prototyped with the materials to hand. I might get some ali for the jaws, the thread would probably need to be steel.

Remember that Ali tends to react after prolonged contact with Steel. You might go to do the clamp up one day to find the Ali threads turned to powder....

[MrBowcat]

Good point. Maybe carbon fibre rod might be a better option. I would use Ali rod but might get galling.

[RangerNeil]

Or perhaps Ali or nylon for the clamp blocks? You won't be putting much pressure on them for modelling....